422 PRACTICAL BOTANY 



with pollen from other individuals, but that these should, as far 

 as possible, all be of the same stock. It is not sufficient that 

 all should be of the same variety ; the most rapid progress 

 will be attained if all the parent plants are descended from 

 the same ear of corn. 



It will not be necessary to give in detail all the methods 

 followed in the selection of seed, and the precautions which 



FIG. 337. Cross-pollination and self-pollination 



The effect of cross-pollination and of self-pollination on the growth of corn from 

 the seed. The two rows of spindling plants at the left grew from seed produced by 

 self-pollination, the larger plants of the other rows from seed produced by cross- 

 pollination. Photograph furnished by Funk Bros. Seed Co. 



are adopted to prevent mixture of varieties in the growing 

 crop. Successful corn breeding demands: 



(1) The choice of the most desirable known variety as a 

 basis for breeding for any given purpose. 



(2) Selection of well-matured ears from the best plants 

 in the field. 



(3) Growing trial rows the next season from the ears of 

 (2), each ear planted in a row by itself. Every other row 

 should be detasseled to prevent the plants from pollinating 



